The basic model of digital printing over a network is well known. A population of computers, each of which may hold document data which is desired to be printed, communicates with a population of digital printers, using a print protocol such as Raw or LPR (Line Printer Request) over TCP/IP. An IP network address of a “target printer” on which the document data in the computer is desired to be printed is used by one computer to identify, and initiate communication with, the target printer. Once contact is made, Raw or LPR protocol is used to submit the document data.
In a practical network context, where a computer on a network is desired to send a set of data to be printed (herein, a “document”) to a desired target printer, other parameters, “settings,” must be determined and taken into account. First, even if the IP address of the target printer is determined, it must further be known what the “printer port” of the printer is. Printer port is a TCP/IP port on which the digital printer accepts print requests or documents. The printer port can be classified into two categories, ones that support Raw print job submission and the ones that support LPR submission. Raw printer port accepts print jobs using the standard TCP/IP communication commands, whereas LPR defines a set of commands which have to executed to submit the print job. Different printer vendors have different “printer port” numbers for their machines: common Raw printer port numbers are 9100, 2000, or 2105. In case of LPR, the port number is 515, as is common in legacy UNIX® printing applications. With LPR, there must further be submitted what is called a “queue name,” which enables a type of handshake between the computer and the target printer. The queue name identifies the print channel/queue to be used by the printer; an incorrect value will lead to failure of the document submission.
In a typical network environment such as managed corporate intranet, all of the computers and printers on the network are managed with a network server. The network server typically retains, and regularly updates, a network directory of all printers and related devices directly accessible to it. The network directory retains, for each printer, information about the other necessary parameters, such as port numbers, print protocol (Raw/LPR) and other settings (e.g., queue name in case of LPR), so that any computer on the network can use this information when submitting a document thereto.
With the emergence of sophisticated portable computers and computer-like devices, such as lap-tops, personal data assistants, digital cameras, wireless telephones, pagers, etc. (hereinafter generically called “computers”), it is becoming common that a human user may wish to print a document on a printer which is located in an unfamiliar building to which he has brought his computer. Ordinarily, such a human user would have to ask the local system administrator to let him get on the local network, and in turn receive the necessary parameters or settings for printing on a selected printer in the building.